• 한국지반환경공학회 논문집
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• 제25권5호
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• pp.39-47
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• 2024

본 연구에서는 재활용 시 도로용이나 지반 보강재로 사용되는 전기로 제강슬래그의 입경별 중금속 용출 실험과 제강슬래그와 점토를 혼합한 혼합비별 공시체의 이온 용출을 실험하여 환경적 특성을 분석하였다. 폐기물 공정시험결과 시료 시험항목에서 중금속은 검출되지 않은 것으로 나타났으며, 물과 접하지 않은 제강슬래그의 경우 용출이 일어나지 않는 것을 알 수 있었으나, 제강슬래그의 중금속 용출 실험을 진행하여 ICP-OES 분석한 결과 일부 중금속이 검출되었다. 제강슬래그가 물과 반응하면 제강슬래그 내에 존재하는 Free CaO와 화학반응이 일어나 용출이 되는 것을 알 수 있었다. 제강슬래그의 입경별 용출 실험을 진행한 결과 가장 많은 용출이 일어난 알루미늄의 경우 입경이 작을수록 커지는 것으로 나타났으며, 제강슬래그와 점토를 혼합한 혼합토의 경우 제강슬래그의 함량이 증가할수록 알루미늄의 용출량은 증가하였다. 그러나 제강슬래그만을 사용했을 때보다 제강슬래그와 점토의 혼합토에서 용출되는 알루미늄의 양이 현저히 낮아졌으며, 다른 중금속들도 용출되는 양이 기준치 이하로 나타났다. 그러므로 제강슬래그와 점토의 혼합토를 재활용하여 도로용이나 성토용 재료로 사용 시 중금속의 용출에 대한 우려는 매우 낮아질 것으로 사료된다. 이러한 결과는 순수 제강슬래그만을 사용하는 것보다 제강슬래그와 점토를 혼합한 재료가 친환경적으로 지속가능하고 안전한 대안이 될 수 있다고 판단된다.

• 자원리싸이클링
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• 제22권5호
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• pp.13-19
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• 2013

구리, 아연 및 납 등의 중금속으로 오염된 사격장 토양으로부터 중금속 성분을 제거하기 위한 친환경적인 공정을 개발하기 위해 구연산용액을 이용하여 중금속 침출거동에 대한 pH의 영향을 조사하였다. 구연산 침출실험은 구연산과 구연산나트륨을 혼합하여 pH를 조절한 용액을 이용하여 시료입도 $75{\mu}m$이하, 반응온도 $50^{\circ}C$, 구연산 농도 1 몰, 광액농도 5%, 교반속도 100 rpm, 그리고 침출시간 1 시간의 조건에서 진행하였다. 침출반응 전후의 pH 변화는 미미하여 침출에 미치는 수소이온농도의 직접적인 영향은 크지 않은 것으로 판단되었다. 구리, 아연, 납의 제거율은 pH가 증가함에 따라 감소하였고, 열역학적인 계산결과, 이와 같은 침출거동은 중금속 이온이 구연산염 이온종과 착이온을 형성하는 반응과 중금속이온이 수산화이온과 결합하여 수산화물로 침전하는 반응에 의해 결정되는 것으로 분석되었다.

• 대한방사선기술학회지:방사선기술과학
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• 제47권3호
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• pp.213-218
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• 2024

The myocardial nuclear medicine examination is widely performed to diagnose myocardium disease using various radionuclides. Although image quality according to radionuclides has improved, the radiation exposure for target organ as well as peripheral organs should be considered. Here, the aim of this study was to evaluate absorbed dose (Gy) for peripheral organs in myocardial nuclear medicine scan from myocardium according to various scan environments based on Monte Carlo simulation. The simulation environment was modeled 5 cases, which were considered by radionuclides, number of injections, and radiodosage. In addition, the each radionuclide simulation such as distribution fraction was considered by recommended standard protocol, and the mesh computational female phantom, which is provided by International Commission on Radiological Protection (ICRP) 145, was used using the particle and heavy ion transport code system (PHITS) version 3.33. Based on the results, the closer to the myocardium, the higher the absorbed dose values. In addition, application for dual injection for radionuclides leaded to high absorbed dose compared with single injection for radionuclide. Consequently, there is difference for absorbed dose according to radionuclides, number of injections, and radiodosage. To detect the accurate diseased area, acquisition for improved image quality is crucial process by injecting radionuclides, however, we need to consider absorbed dose both target and peripheral inner organs from radionuclides in terms radiation protection for patient.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.334-336
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• 2003

Recently, considerable researches have been focused to find out inexpensive sorbents. for removal of heavy metals in aquatic environments. In particular, various natural materials including geologic media have been attractive. In order to evaluate the applicability of the scoria taken from the Jeju island, Korea, to remove Zn(II) from aqueous solutions, the kinetic sorption experiments were performed in this study. The batch-type kinetic sorption tests were carried out under different conditions, such as different initial Zn(II) concentration, particle size of the scoria, and sorbate/sorbent ratio. The results indicated that the removal of Zn(II) by scoria increased with decreases in initial Zn(II) concentration, particle size of the scoria, and sorbate/sorbent ratio. However, the sorption capacity of the scoria decreased with increasing amount of the scoria. The sorption behavior of Zn(II) onto scoria seemed to be mainly controlled by cation exchange.

• Nuclear Engineering and Technology
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• 제40권7호
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• pp.533-538
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• 2008

In some situations, for example at very low doses, in microbeam irradiation experiments, or around high energy heavy ion tracks, use of the absorbed dose to describe the energy transferred to the irradiated target can be misleading. Since absorbed dose is the expected value of energy per mass it takes into account all of the targets which do not have any energy deposition. In many situations that results in numerical values, in Joules per kg, which are much less than the energy deposited in targets that have been crossed by a charged particle track. This can lead to confusion about the biochemical processes that lead to the consequences of irradiation. There are a few alternative approaches to describing radiation that avoid this potential confusion. Examples of specific situations that can lead to confusion are given. It is concluded that using the particle radiance spectrum and the exposure time, instead of absorbed dose, to describe these irradiations minimizes the potential for confusion about the actual nature of the energy deposition.

• Journal of the Korean Wood Science and Technology
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• 제14권4호
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• pp.1-7
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• 1986

This investigation involves a study of the physical and chemical factors of Pinus densiflora SIEB. et ZUCC. and Quercus mongolica Fisher barks affecting on the adsorption of heavy mteal ions. The results obtained can be summarized as follows. 1. The capacity of the untreated bark to remove the Cu and Cd from solution was similar to or 5% higher than that of formaldehyde treated bark in both species. Considering that untreated bark lead to color-leaching problem, bark treated with formaldehyde are economical. 2. With decreasing particle size of bark(20-80), the adsorption ratio of the Cu and Cd from solution was increased. Quercus bark adsorbed more Cu and Cd at smaller particle size compared to Pinus bark. 3. The heavy metal eqilibrium adsorption of the bark from Cu and Cd solution was attained within 10 min. Pinus bark removed about 48% of the Cu and 41% of the Cd from solution in 10 min while Quercus bark removed about 50% during that period. 4. As the initial metal concentration increased. the absolute metal uptake was increased while percentage removal was decreased. At the lower metal concentration (10 ppm). Pinus and Quercus barks removed 77-94% of the Cu and 72-84% of the Cd. At high metal concentration (200 ppm), the adsorption ratio was 40% Cu and 25% Cd, respectivelty. 5. The maximum adsorption of the Cu and Cd from solution was obtained at pH 5-6 in filtrate. 6. With increased bark weight per given metal concentration, absolute removal of metal ion from solution was increased, but the percentage removal was decreased. The amount of adsorption was 4.2 mg Cu and 4.2 mg Cd per gr. Pinus, bark and 5.4 mg Cu and 4.3 mg Cd per gr. Quercus bark, respectively.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2001년도 추계학술발표회
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• pp.23-26
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• 2001

Batch test and column test were performed to develop the design factors for PRBs against the contaminated groundwater by ammonium and lead. Clinoptilolite, one of the natural zeolites having excellent cation exchange capacity(CEC), was chosen as the reactive material through the ion-exchange mechanism. In the batch test, the reactivity of Clinoptilolite to ammonium and lead was examined with varying the particle size of Clinoptilolite. The nit weight of Clinoptilolite showed removal efficiencies of 65 % against the ammonium and 98% against lead. The effect of particle size of Clinoptilolite was not noticeable. In the column test, the permeability was examined using flexible-wall permeameters with varying the particle size of Clinoptilolite. When the washed Clinoptilolite having the diameter of 0.42-0.85 nm was mixed with Jumunjin sands in 20:80 ratio (w/w), the highest permeability of 2$\times$10$^{-3}$ -7 x 10$^{-4}$ cm/s was achieved. The reactivity and the strength property of the mixed material were investigated using fixed wall column having 8 sampling ports on the wall and the direct shear test, respectively. Clinoptilolite was found to be a suitable material for PRBs against the contaminated groundwater with ammonium and/or heavy metals.

• Journal of Radiation Protection and Research
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• 제41권2호
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• pp.123-131
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• 2016

Background: With the increase in the number of particle accelerator facilities under either operation or construction, the accurate calculation using Monte Carlo codes become more important in the shielding design and radiation safety evaluation of accelerator facilities. Materials and Methods: The calculations with different physics models were applied in both of cases: using only physics model and using the mix and match method of MCNPX code. The issued conditions were the interactions of 600 MeV proton and $290MeV{\cdot}n^{-1}$ oxygen with a carbon target. Both of cross-section libraries, JENDL High Energy File 2007 (JENDL/HE-2007) and LA150, were tested in this calculation. In the case of oxygen ion interactions, the calculation results using LAQGSM physics model and JENDL/HE-2007 library were compared with D. Satoh's experimental data. Other Monte Carlo calculations using PHITS and FLUKA codes were also carried out for further benchmarking study. Results and Discussion: It was clearly found that the physics models, especially intra-nuclear cascade model, gave a great effect to determine proton-induced secondary neutron spectrum in MCNPX code. The variety of physics models related to heavy ion interactions did not make big difference on the secondary particle productions. Conclusion: The variations of secondary neutron spectra and particle transports depending on various physics models in MCNPX code were studied and the result of this study can be used for the shielding design and radiation safety evaluation.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.344-349
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• 2016

Background: Carbon ion therapy has achieved satisfactory results. However, patients have a risk to get a secondary cancer. In order to estimate the risk, it is essential to understand particle transportation and nuclear reactions in the patient's body. The particle transport Monte Carlo simulation code is a useful tool to understand them. Since the code validation for heavy ion incident reactions is not enough, the experimental data of the elementary reaction processes are needed. Materials and Methods: We measured neutron production double-differential cross-sections (DDXs) on a carbon bombarded with 430 MeV/nucleon carbon beam at PH2 beam line of HIMAC facility in NIRS. Neutrons produced in the target were measured with NE213 liquid organic scintillators located at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. Results and Discussion: Neutron production double-differential cross-sections for carbon bombarded with 430 MeV/nucleon carbon ions were measured by the time-of-flight method with NE213 liquid organic scintillators at six angles of 15, 30, 45, 60, 75, and $90^{\circ}$. The cross sections were obtained from 1 MeV to several hundred MeV. The experimental data were compared with calculated results obtained by Monte Carlo simulation codes PHITS, Geant4, and FLUKA. Conclusion: PHITS was able to reproduce neutron production for elementary processes of carbon-carbon reaction precisely the best of three codes.

• 자원환경지질
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• 제28권3호
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• pp.231-241
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• 1995

It is well known that hydroxyapatite [$Ca_{10}(PO_4)_6(OH)_2$] have an exchangeability for various heavy metal ions in aqueous solution. To evalute the feasibility of employing the synthetic hydroxyapatites as an eliminatable exchanger for environmentally noxious caions in waste water, the adsorption properties, the removal capacities and the selectivity of the apatites for various cations were investigated in more detailed. The heavy metal cations have been exchanged in calcium part of hydroxyapatite. The order of the degree of amount exchanged of the investigated cations is $Pb^{2+}>Cd^{2+}>Zn^{2+}>Ba^{2+}$. The molar ratios between released $Cd^{2+}$ ions and remeved divalent metal cations in the reacted solution with hydroxyapatite are roughly close to an integer 1.0, suggesting that an ion-exchange reaction could have played a major role in the removal of heavy metals rather then an adsorption effect. The exchangeability of the hydroxyapatite powder of Ca/P molar ratio 1.67, which have specipic surface area of $104.5m^2g^{-1}$, appeared to be better then $237.6{\mu}g$ per g for $Pb^{2+}$ ions. The removal capacity of the heavy metal ions varies directly as particle size of hydroxyapatites. All evidences obtained indicate that the synthesized hydroxyapatite powders by precipitation reaction method can be employed as an effective cation exchanger for eliminating noxious ions in waste water even in some improvemental.